Addictive disorders are chronic conditions for many women. Substance use during pregnancy is especially worrisome. Moreover, major depressive disorder often co-occurs with substance abuse among women. Therefore, pregnant women with substance abuse are complex patients. Priority populations (e.g., minority group members) are greatly over-represented among pregnant substance abusers. Treatment can be effective for female substance abusers but few (if any) data are available regarding comparative effectiveness of residential versus outpatient treatment for pregnant women with addictions. Residential treatment, by definition, provides shelter and reduces availability of substances in addition to delivering care for chemical dependency. However, residential treatment removes patients from their usual home and work environments and is more expensive than outpatient care. Although not focusing on pregnant substance abusers, studies have generally found little difference in outcomes for residential versus outpatient chemical dependency treatment. On the other hand, research has also suggested patient factors (such as addiction severity) may moderate treatment impact so that sub-groups of substance abusers differentially benefit from residential (versus outpatient) care. To address these issues, the proposed project responds to RFA-HS-10-009: Recovery Act 2009 Limited Competition OS ARRA: Comparative Effectiveness Research to Optimize Prevention and Healthcare Management for the Complex Patient (R21). The work will be an analytic epidemiologic study addressing "the benefits and harms of preventive or therapeutic interventions in 'real world'settings for patients who have multiple chronic co-morbid conditions." The chief focus will be pregnant women (many of whom also have major depressive disorder) obtaining treatment for chemical dependency. Two of the co- occurring conditions are substance abuse and pregnancy (both are in the current list of conditions given in the Request for Applications). As required by the Request for Applications, a physical condition (pregnancy) will be addressed. Many participants will have (as a third co-existing condition) major depressive disorder (which is also listed in the Request for Applications). In compliance with the Request for Applications, the study population will include (as a comparison group) female substance abuse treatment patients who are not pregnant. The intervention will be specialty sector substance abuse treatment. The "real world" settings will be publicly financed substance abuse treatment programs. Among several data sets, the project will employ newly available information from the nation-wide Treatment Episode Data Set discharge database. Innovative statistical techniques (including non-linear instrumental variables approaches) will be employed. Comparative effectiveness of outpatient versus residential substance abuse treatment will be examined. PUBLIC HEALTH RELEVANCE: Addictive conditions (often compounded by major depressive disorder) are major problems for many pregnant women. But there is little or no information about comparative effectiveness of outpatient versus residential substance abuse treatment for these complex patients. This project uses newly available national data plus innovative statistical techniques to address this topic which is of substantial public health relevance.